As liquid ejection devices having a liquid ejection head that can eject liquid in a droplet state, there are offered, for example, image recording devices that record an image or the like on a recording medium by ejecting ink droplets, electrode forming devices that form an electrode by ejecting electrode material in a liquid state onto a substrate, biochip manufacturing devices that manufacture a biochip by ejecting living specimen, and micropipettes that eject a sample in a predetermined amount into a reservoir.
This type of liquid ejecting devices reserves ejecting liquid in a reservoir, then supplies the liquid to a liquid ejection head, and ejects the liquid, to which a pressure has been applied in a pressure generating chamber in the liquid ejection head, from a nozzle as droplets toward an object. Herein, there are cases where when the droplets land on the object, splashes adhere to the surface having nozzles (hereinafter, referred to as a nozzle formed surface) and contaminate the surface.
Further, there are also cases where when liquid is ejected from nozzles, finer droplets (satellites) are generated, separating from droplets that land on an object. The satellites may not reach the object and may hang in the air to adhere to the nozzle formed surface.
Still further, there are cases where droplets remain adjacent to nozzles, when the nozzle formed surface is sealed with a cap member and a negative pressure from a suction pump is applied to forcibly suck and discharge liquid from the nozzles so that clogging of the nozzles are resolved.
If a nozzle formed surface of a liquid ejection head, particularly the peripheral of the nozzles, is contaminated in such a manner, it is possible that the ejecting direction of droplets is deviated from a normal direction or the nozzles are clogged to be disabled to eject droplets, which may affect ejection of droplets.
In order to solve these problems, some liquid ejection devices of this type are provided with a wiping mechanism to wipe off contaminants adhered to the nozzle formed surface. Such a wiping mechanism is provided with a wiper blade in a plate form (reed shape) of an elastic material, for example, rubber or elastomer, and is disposed on the home position side which is the waiting area of the liquid ejection head in the liquid ejection device. This wiper blase is located in a normal state at a retreating position where the wiper blade does not contact the liquid ejection head, and at the time of wiping, the upper portion of the wiper blade moves to a wiping position where the wiper blade can contact the nozzle formed surface of the liquid ejection head. Then, when the wiper blade contacts the liquid ejection head, the entire blade is deformed into an arc shape, and the holding member for holding the wiper blade or the liquid ejection head moves, in a state where the front end of the blade contacts the nozzle formed surface. Thus, the nozzle formed surface is rubbed, and the contaminants adhered to the nozzle formed surface are wiped off by the wiper blade.
The liquid having been rubbed off from the nozzle formed surface is adhered to the wiper blade having rubbed the nozzle formed surface of the liquid ejection head. If this state is left, the liquid adhered to the wiper blade adheres to the nozzle formed surface in return during the next wiping operation, which contaminates the nozzle formed surface on the contrary, causing problems such as nozzle failure or deviation of ejection.
In this situation, a device in a prior art has been offered which removes liquid adhered to a wiper blade having rubbed a nozzle formed surface, by rubbing the wiper blade with a blade cleaner, so as to maintain the cleaning performance.
For example, in Patent Document 1 (Japanese Patent Publication TOKKAI No. H10-291324), disclosed is a technology in which a blade cleaner is made contact with a blade strong elastically without rotation during forward motion, and is made contact with the blade light elastically with rotation during backward motion.
In Patent Document 2 (Japanese Patent Publication TOKKAI No. 2000-343719), disclosed is a technology in which wiping operation is performed only on nozzle arrays that need wiping operation.
In Patent Document 3 (Japanese Patent Publication TOKKAI No. 2001-277526), disclosed is a technology in which a rotary type of a blade for cleaning the nozzle formed surface of a recording head by wiping is provided.
In Patent Document 4 (Japanese Patent Publication TOKKAI No. 2001-347675), disclosed is a technology in which mixing of colors of respective inks due to splashed ink is prevented by disposing a division plate between heads during wiping.
In Patent Document 5 (Japanese Patent Publication TOKKAI No. 2005-205640), disclosed is a technology in which a wiper blade and scraper rub each other during forward motion, and the scraper retreats from the wiper blade during backward motion.
In Patent Document 6 (Japanese Patent Publication TOKKAI No. 2005-238643), disclosed is a technology in which mixing of colors is prevented by providing notched portions for division between scrapers for respective colors.
For example, in a case of a full-color inkjet recording device that is a liquid droplet ejection device using liquid ejection heads, a recording head for ejection of K (black) ink and recording heads for ejection of respective color inks, such as Y (yellow), C (cyan), M (magenta), or the like, namely plural recording heads, are mounted on the device.
Further, sometimes, ink is sucked selectively only from heads with which ejection failure, such as nozzle failure or deviation of ejection, has occurred, for a smaller amount of ink waste during suction of ink. Herein, preferably, only the heads from which ink has been sucked are selectively wiped with a wiper blade. It is because, through wiping heads from which ink has not been sucked (hereinafter, also referred to as null wiping), the wiper blade may drag foreign matter to damage the heads or wiping itself may cause nozzle failure. Further, the wiper blade may be worn, which significantly shortens the life of the wiper blade.
A lot of ink is adhered to a wiper blade having wiped a head from which ink had been sucked. In this situation, if ink is removed by rubbing the wiper blade, which have wiped, with a blade cleaner, as in a prior art, then ink from the wiper blade having wiped splashes and adheres to neighboring wiper blades, causing mixing of colors and ejection failure.
In order to solve this problem, a wiper blade may be fallen to the side opposite to the moving direction (rubbing direction) during wiping. However, with such a structure, a large force is applied to means for holding the wiper blade during wiping, which may suddenly fall the wiper blade, disabling enough wiping. In order to solve this problem, it is necessary to lock the wiper blade during wiping, causing a problem of making the mechanical structure complicated.
With this background, an object of the present invention is to provide a liquid ejection apparatus and maintenance method of liquid ejection heads, wherein it is possible to maintain cleaning performance, preventing contamination of a wiper blade caused by liquid splashed from a neighboring wiper blade. Herein, prior to the splashing of the liquid, liquid had been adhered to the neighboring wiper blade following selective rubbing of a nozzle surface by the neighboring blade and has been removed from the neighboring blade by rubbing with a blade cleaner.
Other objects of the invention will be made apparent by the following description.